mac80211: Allow station mode SAE to be implemented in user space

SAE uses two rounds of Authentication frames and both rounds require
considerable calculation to be done. This commit extends the existing
station mode authentication request to allow more control for user
space programs to build the SAE fields and to run the authentication
step ones. Only the second round with authentication transaction
sequence 2 will result in moving to authenticated state.
Signed-off-by: Jouni Malinen <j@w1.fi>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/ieee80211_i.h

@@ -378,8 +378,9 @@ struct ieee80211_mgd_auth_data {
 	u8 key_len, key_idx;
 	bool done;
 
-	size_t ie_len;
-	u8 ie[];
+	u16 sae_trans, sae_status;
+	size_t data_len;
+	u8 data[];
 };
 
 struct ieee80211_mgd_assoc_data {

net/mac80211/main.c

@@ -599,6 +599,7 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
 		wiphy->flags |= WIPHY_FLAG_HAS_REMAIN_ON_CHANNEL;
 
 	wiphy->features = NL80211_FEATURE_SK_TX_STATUS |
+			  NL80211_FEATURE_SAE |
 			  NL80211_FEATURE_HT_IBSS;
 
 	if (!ops->set_key)

net/mac80211/mlme.c

@@ -1917,6 +1917,7 @@ ieee80211_rx_mgmt_auth(struct ieee80211_sub_if_data *sdata,
 	case WLAN_AUTH_OPEN:
 	case WLAN_AUTH_LEAP:
 	case WLAN_AUTH_FT:
+	case WLAN_AUTH_SAE:
 		break;
 	case WLAN_AUTH_SHARED_KEY:
 		if (ifmgd->auth_data->expected_transaction != 4) {
@@ -1936,6 +1937,15 @@ ieee80211_rx_mgmt_auth(struct ieee80211_sub_if_data *sdata,
 	ifmgd->auth_data->timeout = jiffies + IEEE80211_AUTH_WAIT_ASSOC;
 	run_again(ifmgd, ifmgd->auth_data->timeout);
 
+	if (ifmgd->auth_data->algorithm == WLAN_AUTH_SAE &&
+	    ifmgd->auth_data->expected_transaction != 2) {
+		/*
+		 * Report auth frame to user space for processing since another
+		 * round of Authentication frames is still needed.
+		 */
+		return RX_MGMT_CFG80211_RX_AUTH;
+	}
+
 	/* move station state to auth */
 	mutex_lock(&sdata->local->sta_mtx);
 	sta = sta_info_get(sdata, bssid);
@@ -2762,13 +2772,23 @@ static int ieee80211_probe_auth(struct ieee80211_sub_if_data *sdata)
 	drv_mgd_prepare_tx(local, sdata);
 
 	if (auth_data->bss->proberesp_ies) {
+		u16 trans = 1;
+		u16 status = 0;
+
 		sdata_info(sdata, "send auth to %pM (try %d/%d)\n",
 			   auth_data->bss->bssid, auth_data->tries,
 			   IEEE80211_AUTH_MAX_TRIES);
 
 		auth_data->expected_transaction = 2;
-		ieee80211_send_auth(sdata, 1, auth_data->algorithm, 0,
-				    auth_data->ie, auth_data->ie_len,
+
+		if (auth_data->algorithm == WLAN_AUTH_SAE) {
+			trans = auth_data->sae_trans;
+			status = auth_data->sae_status;
+			auth_data->expected_transaction = trans;
+		}
+
+		ieee80211_send_auth(sdata, trans, auth_data->algorithm, status,
+				    auth_data->data, auth_data->data_len,
 				    auth_data->bss->bssid,
 				    auth_data->bss->bssid, NULL, 0, 0);
 	} else {
@@ -3329,19 +3349,33 @@ int ieee80211_mgd_auth(struct ieee80211_sub_if_data *sdata,
 	case NL80211_AUTHTYPE_NETWORK_EAP:
 		auth_alg = WLAN_AUTH_LEAP;
 		break;
+	case NL80211_AUTHTYPE_SAE:
+		auth_alg = WLAN_AUTH_SAE;
+		break;
 	default:
 		return -EOPNOTSUPP;
 	}
 
-	auth_data = kzalloc(sizeof(*auth_data) + req->ie_len, GFP_KERNEL);
+	auth_data = kzalloc(sizeof(*auth_data) + req->sae_data_len +
+			    req->ie_len, GFP_KERNEL);
 	if (!auth_data)
 		return -ENOMEM;
 
 	auth_data->bss = req->bss;
 
+	if (req->sae_data_len >= 4) {
+		__le16 *pos = (__le16 *) req->sae_data;
+		auth_data->sae_trans = le16_to_cpu(pos[0]);
+		auth_data->sae_status = le16_to_cpu(pos[1]);
+		memcpy(auth_data->data, req->sae_data + 4,
+		       req->sae_data_len - 4);
+		auth_data->data_len += req->sae_data_len - 4;
+	}
+
 	if (req->ie && req->ie_len) {
-		memcpy(auth_data->ie, req->ie, req->ie_len);
-		auth_data->ie_len = req->ie_len;
+		memcpy(&auth_data->data[auth_data->data_len],
+		       req->ie, req->ie_len);
+		auth_data->data_len += req->ie_len;
 	}
 
 	if (req->key && req->key_len) {